Plasma evolution from laser-driven gold disks. II. Computational design and analysis

The lasnex computer code [Comments Plasma Phys. Controlled Fusion 2, 51 (1975)] was used in the design and analysis of an experimental study of laser-driven plasma blowoff from gold disks. In the study, several temporal profiles of 0.53 mm laser illumination were used, including square pulses, picket pulse trains, and pulses with graduated leading edges. Preliminary modeling suggested diagnostic techniques [time- and space-resolved imaging of M-band x-ray emission and time- and space-averaged measurements of high-energy (3.5–20 keV) x-ray spectra] that complemented diagnostics already used in such experiments (four-frame holographic imaging to determine the electron-density profile in the underdense corona plasma). In this article, the lasnex results are analyzed and are compared with the measured plasma electron-density profiles and with time- and space-averaged measurements of the corona temperature. The simulation tracks the observed electron-density profiles fairly well during the early portions of the laser drive, during which the spatial profiles are approximately self-similar, but overestimates the electron density in the later, steady-state segment of the profile. For the corona electron temperature, simulation and experiment agree to within the experimental accuracy of ±20%.